CHNOPS! The six most common elements that make up living things are

• Carbon
• Hydrogen
• Nitrogen
• Oxygen
• Phosphorus
• Sulfur

You will need to know these elements and be able to list which elements are most commonly part of living things. It's easy to remember them if you pronounce their initials as a single word. Cha-nops (or Schnops on the college circuit) is the easiest way to remember these elements.

You also may note that these are some of the lighter elements on the periodic table. Elements #1, #6, #7, #8, #15 and #16 make up most ov the living things on the planet. All you really have to do is learn these six.